As various kinds of electronic equipment, e.g. a portable telephone and small personal computer, has had more advanced or diversified functions in recent years, there is an increasing number of so-called folding type equipment in which a movable housing is attached to a fix housing of the equipment so that the movable housing can be opened and closed with respect to the fix housing. An opening and closing device for use in this type of equipment also requires that the opening and closing position should be securely held. Japanese Patent Unexamined Publication No. 2002-89542 discloses an example of those devices.
However, there has been no comparative opening and closing device that can satisfy comfortable opening and closing operations and secure opening and closing states at the same time.